There are a total of four observation periods (during they are hospitalization various four times)(there are five days in each period ) (O) for each diagnosed child with cancer , during next four consecutive hospitalizations for chemotherapy. The data from this study will be used to analyze the trend of symptom changes and will be as the control group. 2011/7~2012/12, an intervention (X) of two 20-minute walking will be implemented into their daily activity, one in the morning and the other one in the afternoon. Then four observation periods with the same procedures, frequency, and other described measures will be used to collect data.